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Urchin writes "The quality of sunlight varies depending on where you live, but off-the-shelf solar cells are all identical. A new solar cell designed by UK firm Quantasol is easily tuned to adapt to the local light conditions, which boosts its long-term performance. Its short-term performance isn't bad though — the single junction solar cell has a peak efficiency greater than any previous device, beating a world record that's stood for 21 years."

I know I'm heading to the moderation cellar for this, but COME ON guys, don't be so damn lazy about your language. See my sig below.

That kind of mistake is a huge cognitive speed bump for many readers. You're blowing your chance to communicate with your audience when you make (and belittle complaints about) adolescent mistakes like this.

I know I'm heading to the moderation cellar for this, but COME ON guys, don't be so damn lazy about your language. See my sig below.

That kind of mistake is a huge cognitive speed bump for many readers. You're blowing your chance to communicate with your audience when you make (and belittle complaints about) adolescent mistakes like this.

The sigs are often more memorable than the usernames, and they tell you a little bit about the account's owner, so I just leave them on. What annoys me is when someone types in a sig at the bottom of their post which says the exact same thing as the sig below it....or when they sign their post with their username =/ I guess I'm just being picky though.

There's a difference between a decision of style (vs vs vs. - both are OK, it's a common stylistic choice not to use a period when an abbreviation ends with the last letter of a word, as in "Dr" or "Rd"), and an actual spelling mistake.

It's more than style. There's an important difference between, say, 'St' and 'St.' (saint and street - ever come across 'Liverpool Saint Station'?). Abbreviations end with a dot, contractions without. There's no problem at all with 'vs' for 'versus'.

Abbreviations end with a dot, contractions without. There's no problem at all with 'vs' for 'versus'.

If it's a contraction, it should be "v's". If it's an abbreviation, it should be "vs." If it's an acronym, it should be "VS". But in no case is "vs" appropriate under the rules used here. Contractions get apostrophes, abbreviations get periods, and you pick what you want "vs" to be, but it has to have some punctuation to meet the rules used here.

A contraction is a word shortened by removing letters from the middle and an abbreviation is a word shortened by removing letters from the end. Presumably you spell it v's, but that's a little ugly and certainly not conventional. No punctuation is entirely normal where I come from. There's a wikipedia article with more: http://en.wikipedia.org/wiki/Contraction_(grammar) [wikipedia.org]

Adding a period is being lazy? I think rather that lazy people would seek to reduce the number of markings needed on a page to convey the same idea (note "ur" versus "you are" or "your" or "you're"). The reasoning would be more like:

We got stupid and forgot which abbreviations need a period and which ones don't.We got stupid and couldn't tell abbreviations apart from full.We simplified the abbreviation rules to have a period at the end of all abbreviations.

That's just silly. These rules are a matter of convention, and some of these conventions were adopted as late as the 20th century. The British make distinctions between an abbreviation (where you leave off the end-part of a word) and a contraction (where you drop the middle part), whereas Americans and Canadians don't so much, and this is where some of the difference lies. The examples you gave with the trailing period are technically contr

They are ALL lazy. Not just Slashdot. Since everything went online the quality of spelling and grammar has hit Elementary school levels. AP, Reuters, The New York Frikkin' Times, etc. ALL have various errors these days.

My mind seems to auto-correct for these mistakes pretty quickly while I am reading, but it does make me wonder if we would not be better off hiring 3rd graders to write these things out instead of journalism majors.

Let's face it. If you don't get a red line underneath what you are typing

Does anyone else see the irony in this post? No? Well that's because all of us have the great advantage of the neocortex. You see, when you see a word in context, even if it's spelled wrong its meaning is properly interpreted. I know it's useless to yell at you grammar Nazis, but I have this small shimmer of hope that this message will make the following posters WRITE ABOUT FUCKING SOLAR ENERGY.

Actually, spelling grammar and punctuation was always horrible. It's just that 15 years ago, the 90% of people who are the poorest language-users, didn't usually publicize a lot of text.The Internet didn't make people worse -- it just made them a lot more visible.

Also, it reduced geographical boundaries, english is my third language, it's not reasonable to expect the same knowledge of ones third language as a mother-tongue. Yeah, I make more mistakes than many native english-speakers, but no, it's not becau

Of course your little rules for using such a thing COMPLETELY forget about the possessive sense. 'It' is a noun and 'it's' can work not as 'it is' but as a possessive statement. Kind of like"This is a cat's dinner bowl. Here is it's water bowl."

In English the apostrophe has two main functions: it marks omissions, and it assists in marking the possessives of nouns and some pronouns. In strictly limited cases, it is allowed to assist in marking plurals, but most authorities now disapprove of such usage. An ap

Eh, beat me to it!
And there have been incremental increases in efficiency across a whole range of cell technologies on a regular basis, including the use of quantum wells, (and other quantum effects), in other materials. In fact, the only reason it's even possible to insinuate any big hoopla about GaAs cells is that they've been around so long a lot of experimenters have stopped trying to improve them. Badly worded article/summary for sure...

My guess is that it's a lot more expensive. Semiconductor devices have to be processed in vacuum conditions and often at high temperatures; and the more precessing you use (triple junction has minimum 4 layers), the higher the cost. This is why there's interest in alternative, non-semiconductor devices like dye-based and conjugated polymer cells. Easy to produce in solution and at low temperature, no vacuum. There's a plethora of other undesirables in semiconductor solar cells too, like weight, inflexibility, etc.

multijunction cells can also perform worse then single junction cells in non-optimum light conditions. A cell's output is effectively throttled by the lowest producing junction (similar to why it's so bad to allow a shadow to fall on part of an array). So if its cloudy or something and most of your light is reflected, you can get more power out of a low-wavelength single junction cell then you can out of a triple junction one.

I hesitate to say because it feels too goddamn obvious but higher efficiency leads to lower cost-per-kWh, so you really should care. What you (or the manufacturer) really should be looking for is the pay-off point - where the improved efficiency matches or beats the older tech in cost-per-kWh terms.

The other point to make however is that irrespective of cost, more efficient technology can mean wider applications - where previously it would be pointless to put a solar panel because of, say, space limitations

More efficient technology does not mean wider applications irrespective of cost. Technology is defined as being more efficient BY what it costs; if it costs less it is more efficient. The science is still interesting but from a practical standpoint whether or not these will be used widely is directly related to the average cost of the electricity it produces. There is a reason that we don't use people pedaling on bicycles to produce electricity; because of the cost. If labor were much cheaper than burning coal then we would use that instead. Unfortunately the cost of labor is influenced by the COST of living.

If the super-efficient solar panels are constructed of rare materials that cost millions of dollars, then the higher efficiency will not necessarily lead to lower cost-per-kWh. The OP does care, they're just being realistic and not jumping to conclusions, which is what you should do when analyzing any investment.

More efficient technology does not mean wider applications irrespective of cost.
In some cases it does, because some applications can only be enabled when power output per limited surface area is above certain critical treshhold. Solar planes, solar blimps, solar-charged portable electronic devices to lesser degree.

It really doesn't. You have an excellent point, and there are certainly many situations where people would be willing to pay a premium for space efficiency, but there is a point at which it would be too expensive for even those applications. Every person, every organization and every project has economic limitations.

But it does. Im speaking about technical feasibility of an application. You need to hit a certain efficiency benchmark per surface area to make some applications ( of photovoltaics ) possible in the first place. For instance 24-hour stratospheric solar flight, i.e. solar-powered UAVs.

You really need to have a certain level of power output per surface area, because there are low bar limits on how little power you can use to fly reliably. These limits are set by other engineering hard limits like battery en

More efficient technology does not mean wider applications irrespective of cost.

True, but solar cells are costly because of the material it is made with currently. If they can take the same material and use less of it to produce the same amount of power, then the price overall goes down.

Now if they invent another material that is more efficient but more costly to produce than the price goes up.

So, in summary, we need to know the cost of the old solar cells as compared to the cost of the new solar cells in order to determine which one gets you "more bang for your buck," which is how anyone tasked with making a financial decision would define "efficiency" in this situation.

This is a semantic debate over the definition of "efficiency" as it would be had between a company engineer and a company economist. If they cost *pinky to mouth* One Million Dollars then they may gather sunlight efficiently but they don't produce electricity cost-efficiently.

I hesitate to say because it feels too goddamn obvious but higher efficiency leads to lower cost-per-kWh, so you really should care.

That's partly true. However, there's an interplay between peak/average efficiency and environmental factors of the light. This means that two panels with the same peak efficiency might produce wildly different ammounts of energy. For example, a panel that maintains its efficieny in dim light would be better suited to the Pacific Northwest or other cloudy climates, while one with a high peak efficiency only in bright light is best for Southwestern sunny states.

Efficiency DOES matter to enable lots of applications, especially when your sunlight-exposed real estate is at premium. For example, PHEVs and EVs getting their top-up charge from roof-mounted panels, solar panels on top of laptop cases and so on.
Most importantly it matters for applications like solar flight [solar-flight.com]. Solar planes of course wouldnt use heavy GaAs silicon cells, but the best of the breed thin-film cells.

A manufacturer does not sell a product for less than it costs to make. The cost to make it includes the cost of the energy that it takes to make it.
Assume I buy a 1 watt cell for $3 (No, you wouldn't buy a single watt cell). At $0.05/kwH, if half the cost was energy, it would take 30 kwH to make the cell. How much energy will I get out of it? Assume 6 hr/day, and the cell lasts for 20 years, then it would produce 44 kwH over its lifetime (1w x 6 hr/day x 365 day / year x 20 years).
Of course, I'm jus

"The commercial market doesn't just want high efficiency, they want the device to be optimised to the environment," he says. "In the past we measured performance in dollars per watt. Now it's cents per kilowatt-hour that's more important."

This actually sounds like they're on the right track, but until I see prices I'm not convinced the process is a cost-saver. Also it sounds like it's only useful in concentrating designs.

They're quite environmentally sound. They're made of arsenic, and many caustic chemicals being used to refine and produce them. In short -- not suitable for mass alternative energy (like just about every other thing called "green").

Reality: Solar power's only economical use right now is for remote sensors and in locations where the power grid cannot reasonably be extended and delivering fuel is impractical.

Solar panels are actually very cheap to get. Drive down a freeway with those solar-powered emergency phones, knock down a few of the poles, take the panel from on top, and install it on your home. They're free to anyone who has the gumption to get them, courtesy of your state highway department!

Solar power is economical for large-scale deployments. That's why Worldwide Energy and Manufacturing has a $52 million backlog.

For an industry that in 2007 had an operating revenue of $253 billion in this country? They're going to need a few more zeros in their backlog. It was only this year that the solar cell industry celebrated break the $1/watt barrier. Meanwhile, I'm getting power piped into my home at a few cents a kilowatt from a nuke plant ten minutes drive from here. And the power plant will last a lot longer than solar cells stapled to some roof will.

Furthermore, it's very disingenuous to compare a commercial large-scale energy source with a localized energy source. Retail costs of solar production are not an apt comparison.

Finally, you need to understand that your electricity is heavily subsidized if you live near a nuke plant. Nuke plant power costs would be around 18 cents per kWH for new plants in the US (and that's a conservative estimate; costs to build plants are skyrocketing, all

Cut-n-paste:Factoring in all these issues, various groups have attempted to calculate a true economic cost for electricity generated by the most modern designs proposed. Because if an actual cost per kW*h can be calculated, then it is possible to compare it to other power sources to determine if such an investment is economically sound.

In 2003, the Massachusetts Institute of Technology (MIT) issued a report entitled, "The Future of Nuclear Power". They estimated that new nuclear power in the US would cost 6

It was only this year that the solar cell industry celebrated break the $1/watt barrier. Meanwhile, I'm getting power piped into my home at a few cents a kilowatt from a nuke plant ten minutes drive from here. And the power plant will last a lot longer than solar cells stapled to some roof will.

Don't spread FUD here if you can't get your physical units right! You get "power" for a few cents per kWh, not kW (they sell you energy, not power actually - the difference is important). The thin-film solar cells have broken 1$ per Watt installed - i.e. per measure of power which will produce energy year-in, year-out (viz. 1 kWh every 42 days) and thus might end up being as cheap as nuclear energy if you count in the nukes' externalities like reprocessing, security, radioactive waste that are mostly dealt

...and thus might end up being as cheap as nuclear energy if you count in the nukes' externalities like reprocessing, security, radioactive waste that are mostly dealt with by the government

In the US at least, nuclear power plant operators are required to pay into the Nuclear Waste Fund [blogspot.com] for just this purpose. "As of March 31, 2005, the total revenue paid into the Nuclear Waste Fund amounted to $24.9 billion. Of that amount, only $8.9 billion has been spent on program costs, leaving a balance of $16.02 billion that has been collected, but not applied to the used nuclear fuel disposal program." So there is a big (and growing) pile of money for whatever long-term solution we eventually settle on.

I am not sure of the degree to which security costs are externalized. I think they pay their own dedicated protective forces, or pay the NRC a security fee. But after 911, the National Guard also got involved, which sounds like an externality, though I don't know whether that was permanent.

When you say $1/Watt, do you mean, at the installation time, or at end of life? The amount of degradation and its speed is particularly important. Also, is the $1/watt the peak power of the panel, or the average over a cloudless year at some reference lattitude?

The $1/watt is for the panel only, without installation, and it is a peak figure - so actually you don't really get 1kWh from a $1 panel in 42 days (that was just for illustration) but about an order of magnitude less. But over the lifetime, this still ends up being very cheap, as the panels now live 25 years without too much degradation (only 20% or so) or a lot of maintenance. (The wiki [wikipedia.org] has some cost estimates: 5 to 20 cents per kWh depending on insolation and installation costs.)

While technically correct, a subsidy is more commonly used to describe an outright grant of money, with no requirement to pay it back. Such as the government subsidizing PBS, or the Arts programs, or giving grants for medical research. A loan guarantee, which is what the article is talking about, is not what most people would call a subsidy.

You could also say that solar technology is highly subsidized by the government, and otherwise isn't profitable.

While technically correct, a subsidy is more commonly used to describe an outright grant of money, with no requirement to pay it back. Such as the government subsidizing PBS, or the Arts programs, or giving grants for medical research. A loan guarantee, which is what the article is talking about, is not what most people would call a subsidy.

Yes, the article does mention a loan guaranty but it also says tax subsidies are used. It also says that because of the large upfront capital costs, "10 to 15 times as

Fuck that. We should just abandon all science and research in energy that is more expensive than nuclear or coal. Yeah, fuck solar power... it might take actual work to get it to be econimically feasable. Meanwhile, we've already speant 100X what it would take to get solar power economically feasable on making nuclear energy economically feasable. We should just stop advancing technology and just stick with what we've already wasted trillions on... that way Joe Nuke's electric bill won't go from $60/month

Along the same vein, I justify driving my old, fuel-inefficient sports car by taking the dinosaurs' viewpoint. They were wiped out by global cooling, man! Releasing all this sequestered carbon dioxide is just my way of saving the planet. Someday when your grandchildren are living in the subtropical paradise that Antarctica will become, you'll thank me.

30%? 40%? Efficiency only matters if you're constrained by space (airplanes) or by weight (satellites). 15%-efficient solar cells are good enough that you can power your house with them by covering your roof -- or would be, if they were produced cheaply and in quantity.

The article mentions the efficiency of the cell at 500x normal sunlight, so the idea here is to use inexpensive mirrors to concentrate the light onto expensive cells. The setup is bulkier, but could be cost effective, even with very expensive cells, since you buy fewer cells. With mirrors and high efficiency cells, you also can get the same power out of a much smaller installation. This setup might not be ideal for residential rooftops, but would work for large flat-roofed buildings and desert installations.

I'll base this on the house where I grew up: a 2000-square-foot single-story house on the outskirts of Seattle:

190 square meters of roof. Assume that only the south-facing side is usable: 85 square meters of sun-facing surface. That's 85kW of sunlight, which at 15% is about 13kW of electricity. Since this is Seattle, assume four usable hours of sunlight a day: 52kWH per day, or about 1560kWH per month. Unless you've got electric baseboard heating (you do find that in the Seattle area), that's more than

Not to belittle this accomplishment, but I'd prefer to see an increase in average efficiency. According to the article the peak efficiency is found when panels are exposed to light 500 times that of normal light. How does that translate to efficiency under normal operating conditions (such as a semi-cloudy day in the midwest)? The article is rather short on details concerning how well the solar cells operate when they are "tailored to their locations."

Not to belittle this accomplishment, but I'd prefer to see an increase in average efficiency. According to the article the peak efficiency is found when panels are exposed to light 500 times that of normal light. How does that translate to efficiency under normal operating conditions (such as a semi-cloudy day in the midwest)?

It translates into an acre of cheap mirrors instead of an acre of expensive solar panels.

If you're already buying an acre or more of heliostatic mirrors, it'd probably be cheaper and more efficient to use a solar fired steam turbine to do the generating. Then, if you use a molten salt reservoir, you have some energy storage for night-time power generation as well.

I also doubt it will be cheaper, once you account for maintenance of the mechanical components.

Yes, I suppose you could use molten salt as a battery for thermal energy. On the other hand, you could use a battery as a battery for electrical energy, and you won't spend the entire day fighting against thermodynamics to keep your reserve from leaking awa

It translates into an acre of cheap mirrors instead of an acre of expensive solar panels.

Not quite the same: concentrating mirrors suck in anything but a perfectly clear day (i.e. no clouds), but a simple non-concentrated PV panel still works quite well with some (not much) cloud coverage. In other words: unless you live in AZ or some other desert, stick with non-concentrated PV panels.

Mirrors are cheaper then solar cells. Being able to focus light onto a solar cell can be a cost effective way of generating electricity - if the solar cell is designed to handle the extra light. The other possible application would be for satellites. Thin reflective foil is much lighter then a solar cell. You would have a similar setup where the foil focuses the light onto a central solar cell.

There is no average efficiency, because unfortunately the bastard that designed this version of Earth didn't make solar radiation distribution gaussian. You could file a complaint with Him, but I understand there's quite a backlog. In the meantime, I'd suggest moving to a desert near the equator if you want to eek out those few extra watts. Whatever you do, don't move to Minnesota -- For some reason, snow and solar panels get along like a big house on fire.

There is no average efficiency, because unfortunately the bastard that designed this version of Earth didn't make solar radiation distribution gaussian.

Perhaps not, however the light that actually reaches the panels is in no way constant. Some days will be cloudier (or smoggier for that matter) than others, so it is great that we have really good peak efficiency with these new cells, but how often will that peak be reached and how well does it operate at less than optimal light conditions? I'm looking for

For some reason, snow and solar panels get along like a big house on fire.

What I heard is that there are small scale, ie residential, solar installations here in MN. Heck even solar thermal water heating [directorym.com] is being used. MN is also good for wind. Though not much the state produces megawatts of energy from wind.

Yes, thank you, you've successfully tested my ability to read and recall memories. What I'd really like to know is how many of these cheap lenses and mirrors will now be necessary vs how many I was using before, and how much more efficient will the operation of storing energy be on days when the sky is not absolutely cloudless? I realize that the solar cell is more efficient at absorbing light, but how can this be applied to a "normal" usage pattern (when we're not talking about 500x the normal amount of

It sounds like the interesting part here isn't the efficiency but that it's efficient enough and can handle a lot of extra sunlight via mirrors. The article fails to give any info though on what kind of efficiency other solar cells can achieve with mirrors focused on them. Without any reference it's hard to get an idea for whether or not this is even useful though.

Spectrolab has the solar cell world record with their triple junction GaAs cells at 40.7% at about 400x or 500x. Amonix Corporation has the silicon world record at 27.6% at approximately the same concentration level.

I am getting bored with all these technological breakthroughs that mysteriously never seem to actually lead to something I can pay money for and get in my hands. Plastic optical memory, I am looking at you, too.